Ultraviolet emission efficiency enhancement of a-plane AlGaN/GaN multiple-quantum-wells with increasing quantum well thickness

Abstract

The defect-induced carrier localization in nonpolar a-plane (Al,Ga)N/GaN multiple quantum wells (MQWs) structures with different well thickness have been investigated. A strong variation of temperature-dependent photoluminescence peak energy was observed and attributed to the existence of the localized states. The degree of carrier localization in these defect-induced states was more prominent in the case of MQWs with the wider well width. In addition, the ultraviolet light emission efficiency revealed a 3-fold enhancement with increasing the well width from 1.6 nm to 7.3 nm, due to the strong carrier localization generated from the quantum-wire-like features formed by the intersection between basal stacking faults and quantum wells. (C) 2012 American Institute of Physics.